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Aug 1, 2018
The Iris Nebula in a Field of Dust
Image Credit & Copyright: Franco Sgueglia & Francesco Sferlazza
Courtesy of http://apod.nasa.gov/apod/astropix.html
The Iris Nebula in a Field of Dust
Image Credit & Copyright: Franco Sgueglia & Francesco Sferlazza
Courtesy of http://apod.nasa.gov/apod/astropix.html
What blue flower grows in this field of dark interstellar dust?
The Iris Nebula.
The striking blue color of the
Iris Nebula is created by light from the bright star
SAO 19158
reflecting off of a dense patch of normally
dark dust.
Not only is the star itself mostly blue, but blue light from the star is preferentially
reflected
by the dust -- the same affect that
makes Earth's sky blue.
The brown tint of the pervasive dust comes partly from
photoluminescence --
dust converting
ultraviolet radiation to
red light.
Cataloged as
NGC 7023, the
Iris Nebula is studied frequently because of the unusual prevalence there of
Polycyclic Aromatic Hydrocarbons (PAHs), complex molecules that are also released on Earth during the incomplete combustion of wood fires.
The bright blue portion of the
Iris Nebula spans about six light years.
The Iris Nebula,
pictured here, lies about 1300 light years distant and
can be found
with a small telescope toward the constellation of
Cepheus.
